Improvement in check and safety valves



. T.DUP FY'. Check and Safety Valve.

Patented Dec. 10,1878.

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UNITED STATES PATENT OFFICE.

TERRENOE- DUFFY, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN CHECK AND SAFETY VALVES.

Specification forming part of Letters Patent No. 210,766, dated December10, 1878 application filed October 24, 1878.

To all whom it may concern:

Be it known that I, TERRENCE DUFFY, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented a new and usefulImprovement in Double Check and Safety Valves, which improvement isfully set forth in the following specification, reference being had tothe accompanying drawings, and to the letters of reference markedthereon.

My invention relates to an improvement in double check and safetyvalves; and consists in the novel combination of two check-valves in oneglobe-one to receive and the other to discharge-by an improvedconstruction of the discharge-valve, in combination with a spring. Thesame can be used as a safetyvalve.

For convenience in illustration, I will proceed to describe my inventionas attached to To enable others skilled in the art to make and use myinvention, I will proceed to describe its construction and operation.

In the drawings, Figure 1 represents the valve as attached to a pump.Fig. 2 is a sectional view of the same as taken through the center line.

A represents the globevalve; B, the valvestem 5 G, thereceiving-chamber; D, the receiving check-valve; E, the discharge-valve.F is the spiral spring inserted in the dischargevalve; G, the bushconnecting the valve with the stem; H, the discharge-chamber.

In operation, the upward stroke of piston exhausts the fluid from thepumpchamber, causing the valve D to rise and admit the fluid into thesame. The downward stroke closes the valve D and raises the valve E,discharging the fluid from the pump through the chamber H.

When used as a safety-valve, I inclose a spring of any desired strengthin the hollow valve E. When the pressure on the face of valve becomesgreater than the strength of the spring the valve E rises, compressingthe spring against the end of the stem B, thus relieving the pressure inthe reservoir to which it may be attached.

Having thus described the nature, construction, and operation of myimprovement, what I claim as my invention is- The combination, in adouble check and safety valve, of the globe A, the receivingchamber 0,the stem B, the receiving checkvalve D, the discharge-valve E, thespiral spring F, the bush Gr, and the discharge-chamber H, all arrangedin combination, substantially as herein described, and for the purposeset forth.

TERRENOE DUFFY.

IVitnesses OLIVER P. JACKSON, JAMES J. LARKIN.

